The invention is in the field of cosmetics and relates to novel anionic surfactant concentrates having defined amounts of alkyl ether sulfates and alkyl sulfates, to a method for the preparation thereof, and to the use thereof in cosmetics.
Alkyl ether sulfates are notable for excellent foaming properties. As well as a high base foam, advantageous foam kinetics are also found, i.e. even in the presence of fats and water hardness a creamy foam is obtained which persists for a long period and does not collapse. Since alkyl ether sulfates are also extremely well tolerated by the skin and have good cleansing properties, they are often used for the preparation of hair and skin cleansing compositions, such as, for example, hair shampoos, shower preparations and the like. A disadvantage, however, is that alkyl ether sulfates do not favor the incorporation of some oily substances, in particular of silicone oils. The formulations are often cloudy and undergo separation, particularly under thermal stress, meaning that further, generally nonionic, emulsifiers have to be co-used. In addition to these application problems, alkyl ether sulfates have the disadvantage that, in high-concentration form, they are virtually cut-resistant pastes which become pumpable only as a result of dilution or warming, which hinders handling.
Accordingly, the object of the present invention was; firstly to provide additives for alkyl ether sulfates so that the miktures are flowable, pumpable and sprayable even in high-concentration form, without the need for the co-use of polyols and consequently without adversely affecting the application properties. Quite the opposite, these novel mixtures should allow the stable incorporation of silicone oils into shampoo formulations.